The need for the medical/dental practitioners to take x-ray images of the human mouth remains as necessary modernly as it has historiocally. Over time the technology has remained the same, but the equipment used to implement the technology has continued to advance.
Contemporarily, if an x-ray image of patient's full mouth is needed, it is done in segments. That is, a film card or image sensor is placed in one quadrant or another of the patient's mouth, the image is taken and the film card removed or the image reviewed on a computer system. A new film card or image sensor is placed in a different quadrant of the mouth and another image taken. This process is repeated until all areas of the mouth have been imaged.
While functional, this method has several serious drawbacks. First, the patient is exposed to multiple x-ray bursts. While the dosages are low, they nonetheless must be repeated in order to make a complete set of images for analysis. Second, the x-ray transmitter is oriented from the outside in. This means that each burst of x-ray energy passes through the patient's cheek, through the teeth and then on to the inner mouth. From there the x-ray energy continues to pass through to the thyroid, and in general is not recommended for women who are pregnant, even if a lead shield is used. This means that for a full set of images, the inner mouth may see as many as eighteen to thirty-six bursts of x-ray energy. According to the American Dental Association, the dosage of x-ray energy received by a dental patient is around 0.150 mSv for a full mouth series.
A third drawback of contemporary methods is that the operator of the apparatus must exit the room while the x-ray burst is applied. This is done to prevent the operator from being exposed to an objectionable accumulation of x-ray energy. A fourth drawback of current methods is the need for the operator to focus the equipment in the blind. That is, the film is placed in the patient's mouth, the operator manipulates the horn of the transmitter, leaves the room and then shoots the image. On many occasions the horn is misaligned, for example, a child moves prior to the burst of energy, thus the shot has to be repeated in order to garner a usable image.
A more advanced technique uses an imaging sensor in the patient's mouth rather than a film card. The imaging sensor is wired to a computer system that receives the x-ray data from the digital image sensor, processes it and then displays it on a screen. While this method improves the time required to take and analyze x-ray images, it still requires the four separate exposures to the x-rays and has the same excess radiation problem.
While these contemporary methods work well enough, what would be desirable would be an apparatus that allows the full mouth to be imaged in one exposure. Moreover, it would be even more desirable if this could be accomplished by an apparatus that prevented the escape of excess x-ray energy to the interior of the patient's mouth.